Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare read-only/idempotent/closed-world safety. The description adds substantial context beyond that: what a country link carries (relationship type and review state), that informative national text is surfaced only as a separate research lead, the coverage-gap semantics ('an absent link is a coverage gap, never proof that national law is absent'), and the auth/cost profile ('ordinary signed-in Nexus allowance').

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the core purpose and keeps each subsequent sentence to a distinct, load-bearing point (output contents, link semantics, coverage-gap rule, scope limit). It is dense and slightly long, but no sentence is pure filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 7 optional parameters, an output schema, and rich annotations, the description covers the behavioral and interpretive context an agent needs. Minor gap: it doesn't hint at how to compose valid role keys or what an empty result implies beyond the coverage-gap note, but the schema handles the mechanics.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema already documents all 7 parameters, including the comma-separated role-key format and date format. The description restates which inputs are available (roles, activity, product, Spain/France, date) without adding syntax or constraint detail beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Research source-bound EU role requirements') and enumerates what it returns: exact passages, act-specific definitions, conditions, unknown facts, and EN/FR/DE/IT source availability. It is clearly distinct from generic siblings like define_term or search, though it never names an alternative tool explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives usage context (select multiple roles, optional activity/product/country/date) and a boundary ('bounded research aid, not a compliance verdict'), which implies when to reach for it. However, it never contrasts itself with the many sibling research tools (define_term, find_national_implementations, guidance_for_provision), leaving the agent to infer the choice.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.